Adjustment of enzyme level in feed to provide the adequate nutrition in starter diet of chicken

by Dr. N.E. Ward, M. de Beer

At hatch, the chick is not adequately prepared to efficiently digest feed. This, plus the changing levels and composition of NSPs over the production period, necessitates an adjustment in enzyme supplementation.

Poultry nutritionists are challenged with providing proper nutrition to the immature intestinal system of the chick during the starter phase. In the days following hatch, the young bird is physiologically limited in the amount of energy, amino acids and other nutritional attributes it can obtain from high-quality feeds (Batal and Parsons, 2002).

Non-starch polysaccharides (NSPs) complicate this process by encumbering nutrients and interfering with digestibility. This is more problematic at an early age, in part because the effects imposed by NSPs are more pronounced in younger chicks.

Still, suboptimal digestibility can be the consequence beyond intestinal immaturity or the presence of NSPs. Poor quality ingredients, disease conditions, starch overloading and other factors can tax feed costs.

Of course, early growth is vital for subsequent performance and meat yield (Ross, 2009). Satellite cells — remarkably dependent on early nutrition — set the stage for muscle development in the mature bird (Halevy et al., 2003).

Cell formation is rapid and transient in the first days of life, and suboptimal nutrition at this age can pervert lifetime performance and limit meat yield (Noy and Sklan, 1999; Halevy et al., 2001).

Substrate accessibility

Carbohydrases, proteases and phytases can potentially resolve some digestibility issues and improve substrate utilization (Adeola and Cowieson, 2011). Many nutritionists use multiple enzymes but often are unsure of the proper combination and how to best account for their value when using least-cost formulation software.
Carbohydrases for NSPs are important because of their contribution to metabolizable energy (ME) — the primary driver for feed costs.

The soluble NSPs associated with wet litter, pasty vents and other performance issues in wheat- and barley-based diets are visibly responsive to xylanases and glucanases. Compared to these grains, however, corn/soybean meal-based diets are far more reticent to carbohydrases (Cowieson, 2010; Slominski, 2011). Corn contains similar amounts of NSPs as wheat, yet nutritional inefficiencies are vague because performance constraints are less conspicuous with corn.

The effectiveness of carbohydrases is greatly affected by NSP accessibility, or the physical proximity of the enzyme to NSP. By sequentially fractionating cell walls in soybean meal to expose NSP components, Ouhida et al. (2001) and others have reported significant increases in enzymatic NSP degradation relative to the intact cell wall.

Reviewed earlier (Feedstuffs, Jan. 27), the NSP in any grain is a complicated composite of different chemical structures and bonds that overlap and intertwine. The sheer density of the cell wall matrix can hinder enzyme penetration to the inner core; thus, systematic degradation by several enzymes is a prudent strategy. Pure cloned enzymes with one major activity may not effectively degrade NSPs in soybean meal or cereals, and the exposure of NSP components simply favors degradation (Huisman et al., 1999).

Broad enzyme selection

Grinding, conditioning and pelleting improves NSP exposure to enzymes, as does gizzard action. Solubility of NSPs, the presence of side chains and the complexity of various types of NSP fiber from different ingredients make the selection of the enzyme mix critical.

In poultry trials with xylanase or glucanase or a combination of protease, amylase and xylanase, Slominski (2011) noted that the lack of response of birds on corn/soybean meal diets indicates that a more diversified group of NSP enzymes seems necessary.

University of Manitoba research found that the complexity of the enzyme mix was highly correlated with improved ileal protein digestibility and feed:gain (Meng et al., 2005). Two simple but important factors were identified: (1) an appropriate group of enzymes is essential and (2) enzyme combinations must target specific NSPs.

Hence, enzymes that are not appropriately paired with NSP substrates exert no benefit. Predictably, an enzyme combination that worked best for soybean meal, canola and peas was not the most optimal for wheat because leguminous NSPs differ significantly from cereal NSPs (Meng et al., 2005).

Xylanase, for example, will serve little purpose with NSPs in soybean and canola meals since the substrate for this enzyme is low in legumes.

Other work concurs that ingredients require carbohydrases specific to the NSP (Malathi and Devegowda, 2001). For corn/soybean meal, pectinase combinations with hemicellulase or with hemicellulase plus cellulase generally showed improved digestibility for protein and organic matter, as well as apparent ME, over the non-enzyme control (Tahir et al., 2006).
In vitro digestibility of corn/soybean meal was improved by a mix of seven enzymes, but individually, only cellulase had the same effect (Saleh et al., 2004).

Certainly, enzymes with debranching side activities should not be overlooked (Huisman et al., 1999). The highly branched nature of corn arabinoxylans, as well as pectins in soybean meal, indicates a need for this type of enzyme. Removing the branches improves exposure of the arabinoxylans to xylanase and the pectins to pectinase.

The primary contribution from feed proteases is improved amino acid digestibility and live performance (Dozier et al., 2010; Angel et al., 2011; Freitas et al., 2011).

A combination of protease and several carbohydrases more effectively solubilized protein and cell wall components in soybean meal than either one did alone at higher concentrations (Marsman et al., 1997). Little work has focused on proteases plus pectinases or galactosidases for corn/soybean meal diets, possibly because pectinases are not widely available.

Some NSPs can chelate phytate (Kim et al., 2005), which is highly associated with protein vacuoles (Bohn et al., 2007). Ileal phosphorus digestibility was more effectively improved with a mix of NSP enzymes plus phytase, as opposed to phytase alone (Woyengo et al., 2010). The appropriate mix of carbohydrases along with protease might permit a greater phytic acid degradation in the presence of phytase.

Dynamic supplementation

The Figure denotes the dynamics taking place over a typical growout period. During this time, the ingredient mix naturally changes to meet nutrient requirements with a least-cost formulation. These modifications are accompanied by changes in dietary NSP composition and level, which can be 10-15% of the feed.

At the same time, the neonate’s gut is rapidly developing. Amino acid digestibility is poor in early versus older ages, leaving a significant amount of dietary protein undigested. Once the digestive system matures, amino acid digestibility increases, leaving less opportunity for exogenous proteases to improve digestion.

From starter to finisher, NSP levels can change 30% or more. In a corn/soybean meal-based diet, for example, NSPs such as pectins and oligosaccharides from soybean meal are a bigger concern during the starter phase. As the growout ensues, inclusion of soybean meal declines while the inclusion levels of corn and dried distillers grains plus solubles (DDGS) increase, meaning arabinoxylans become more prevalent.

As the NSP substrates change, it stands to reason that primary NSP enzymes should change. The same goes for other substrates such as protein, for example, where a protease could make greater contributions early in the feeding period, when protein content is highest.

Enzyme studies

We conducted a series of studies to supplement an enzyme mix to address intestinal tract maturity while simultaneously addressing the substrate levels and types over the life span of the growing broiler. The enzymes target pectins and oligosaccharides, as well as cereal NSPs, protein, starch and phytate.

Previous experimental work helped establish the basis behind enzyme levels to address physiological age and feed substrate levels. These include pectinase, xylanase, amylase, glucanase, debranching enzymes, protease and phytase.

Respiratory chamber research
Indirect calorimetry measures oxygen consumption and carbon dioxide production to quantify nutrient utilization (McLean and Tobin, 1987). Closed respiratory chamber systems with a living animal can assess energy expenditures and can quantify energy losses due to challenges such as coccidiosis (Teeter, 2010). Indirect calorimetry also can provide insight on the efficacy of enzymes for improved ME (Caldas et al., 2014).

In a trial using respiration chambers, Cobb broilers were fed a commercial diet with and without the enzyme product. This enzyme product lowered (P < 0.0006) metabolic oxygen uptake and lowered (P < 0.001) carbon dioxide production (Table 1), indicating a more efficient use of the feed. Ultimately, this translated into improved ME by 51 kcal/kg of final feed.

Previously, researchers at Oklahoma State University found a similar enzyme composition to improve (P < 0.05) the “effective caloric value” (ECV) in feed for broilers (Teeter et al., 2012) when using respiration chambers. The elevated ECV corresponded with improved (P < 0.05) bodyweights and feed:gain in the same study, indicating a good agreement between the chamber research and live performance of floor pen birds.

Chick battery studies
Early research was expanded to include battery studies to test the ability of this enzyme product to improve bodyweight and feed conversion. In one experiment, day old Ross 708 male broiler chicks were randomly allocated across base dietary treatments of corn/soybean meal with 3% corn DDGS.

The enzyme product was added to the negative control diet, which was formulated to be lower in ME, phosphorus and protein compared to the positive control.

The enzyme product increased bodyweight by 6.7% and 5.5% and improved feed:gain by 6.2% and 3.9% on days 10 and 17, respectively, in broiler chicks (Table 2).

The positive control group was fed starter diet similar to typical commercial diets, yet the performance of the negative control plus enzyme group outperformed the control group. This suggests that the enzyme composite eliminated some antinutritional components in the normal starter diet in this trial.

Early life performance is indicative of lifetime performance, and here, 17-day performance was improved over both control groups.

Floor pen research
The final phase in development focused on fl oor pen research in broilers to test the product under conditions similar to those in commercial practice. In one experiment, day-old Cobb x Cobb 500 chicks were randomly allocated at the rate of 45 birds per pen, with 12 replications per treatment.

Diets were consistent with commercial formulations. Deficits in ME, amino acids, phosphorus and calcium were present in the negative control diets. Throughout the life of the bird, the nutritional deficit was recouped by the enzyme mixture without performance loss for either bodyweight,or feed conversion ratio (Table 3).

Each phase was provided a different enzyme composite to account for both physiological development and available substrates. This avoids a conventional static approach with one enzyme or group of enzymes across all feeds, which does not account for intestinal and substrate changes.

Summary

At hatch, the chick is not adequately prepared to efficiently digest feed. This, along with the changing levels and composition of NSPs over the production period, necessitates an adjustment in enzyme supplementation. Appropriate enzyme selection is crucial to account for the range in NSP components in feed ingredients and the levels of physiological maturity. Not all enzyme synergies are understood, but certainly, sufficient information is available to develop multi-component enzymes for corn/soybean meal diets to improve the efficiency of meat production.

References

References are available online to subscribers at www.Feedstuffs.com or by request from tlundeen@feedstuffs.com

Foodborne diseases of poultry and related problems

Published on: 9/18/2019

Author/s : Hafez Mohamed Hafez 1 and Hosny El-Adawy 2,3. / 1 Institute of Poultry Diseases, Free University Berlin, Germany; 2 Friedrich-Loeffler-Institut, Institute of Bacterial Infections and Zoonoses, Jena, Germany; 3 Faculty of Veterinary Medicine, Kafrelsheikh University, Kafr El-Sheikh, Egypt.

Summary

In spite of significant improvement in technology and hygienic practices in developed countries at all stages of poultry production accompanied with advanced improvement in public sanitation foodborne diseases remain a persistent threat to human and animal health. Besides the current legislations, the main strategy to control microbial foodborne hazards should include Good Animal Husbandry Practices (GAHPs) at the farm level through sound hygienic measures, which should be applied to poultry houses and environment and the feed. In addition, reducing colonization by using feed additives, competitive exclusion treatment or vaccines is a possibility during transport and slaughtering. In all cases, agent surveillance and monitoring programmes must be adapted and followed strictly in aim to allow early intervention. In addition, the development of antibiotic resistant bacteria will also be a continuous public health hazard

The present paper describes the general the main strategy to control foodborne infections in poultry, with special attention to European legislations toward safe poultry meat.

Introduction

In spite of significant improvements in technology and hygienic practices at all stages of poultry production in developed countries, accompanied by advanced improvement in public sanitation, foodborne diseases remain a persistent threat to human and animal health. Foodborne diseases are still big issues of major concern in those countries. In developing countries, the need to produce sufficient food to meet the requirements of population increases, accompanied by bad economic situations often overshadow the need to ensure safe food products. Regardless of this fact, safe food is a fundamental requirement for all consumers, rich or poor. Food safety is not a discovery of recent times; it is a natural basic instinct of human survival. During human evolution, several approaches were adopted to achieve safety of food. One of the most famous approaches was practiced by several kings which would employ official and well trusted "tasters" that served as food safety sentinels for the kings and royal family members. Food safety and quality of food are currently big issues of major concern.

Many reports during recent years have shown that Salmonella and Campylobacter spp. are the most common causes of human foodborne bacterial diseases linked to poultry. In some areas also verotoxin producing Escherichia coli 0157:H7 (VTEC), Listeria and Yersinia have surfaced as additional foodborne pathogens causing human illness. Several other toxicogenic bacterial pathogens, such as Staphylococcus aureus, Clostridium perfringens, Clostridium botulinum and Bacillus cereus can also enter the human food chain via contaminated poultry carcasses. In addition, the development of antibiotic resistance in bacteria, which are common in both animals and humans, such as Methicillin Resistant Staphylococcus aureus (MRSA) and Extended-spectrum beta-lactamase (ESBL) bacteria, are also an emerging public health hazard.

Salmonella infection

Salmonella infections in poultry are distributed worldwide and result in severe economic losses when no effort is made to control them. In poultry, the genus Salmonella of the family Enterobacteriaceae, which include more than 2500 serovars, can roughly be classified into three categories or groups as follow: Salmonella can also be divided into three groups based on their host specificity and invasiveness [1]. Invasive salmonellas have the capability to “invade” the body from the intestinal lumen and thus infect organs, causing more serious disease. Group 1 contains serovars, which are highly host adapted and invasive. Examples are S. Gallinarum and S. Pullorum in poultry or S. Typhi in humans. Group 2 contains non-host adapted and invasive serovars. Salmonella in this group are of most concern regarding public health, since some of them are capable to infect humans and food producing animals and especially poultry can serve as reservoirs. There are approximately 10 – 20 serovars in this group. Currently, the most relevant serovars of them are S. Typhimurium, S. Enteritidis, S. Heidelberg, S. Hadar as well as S. Arizonae. Group 3 contains non-host adapted and non-invasive serovars, which are harmless for animals and humans. Most serovars of the genus salmonella belong to this group. Some serovars may be predominant for a number of years in a region or country. Then, they disappear and replaced by another serovars [2]. The infection can be transmitted vertically through contaminated eggs laid by infected carriers as well as horizontally spread (lateral). Hatcheries are one of the major sources of early horizontal transmission. Horizontal spread of Salmonella occurring during the hatching was shown in chickens, when contaminated and Salmonella-free eggs were incubated together. Salmonella can also spread through the hatchery by means of contamination of ventilation ducting, belt slots or door seals within hatchers, but may also result from infection and contamination that continuously recycles between hatchers, hatched birds, dust and crate washing equipment. During rearing the infection is transmitted horizontally (laterally) by direct contact between infected and uninfected flocks, and by indirect contact with contaminated environments through ingestion or inhalation of Salmonella organisms. Subsequently, there are many possibilities for lateral spread of the organisms through live and dead vectors. Transmission frequently occurs via faecal contamination of feed, water, equipment, environment and dust in which Salmonella can survive for long periods. Failure to clean and disinfect properly after an infected flock has left the site can result in infection of the next batch of birds. Significant reservoirs for Salmonella are man, farm animals, pigeons, waterfowl and wild birds. Rodents, pet’s insects and litter beetles (Alphitobius diaperinus) are also potential reservoirs and transmit the infection to birds and between houses [3]. Probably one of the most common sources for lateral spread of the organisms is feed. Nearly every ingredient ever used in the manufacture of poultry feedstuffs has been shown at one time or another to contain Salmonella. The organism occurs most frequently in protein from animal products such as meat and bone meal, blood meal, poultry offal, feather meal and fishmeal. Protein of vegetable origin has also been shown to be contaminated with Salmonella [4, 5].

Since November 2003, several regulations from the European Parliament Council Regulation on the control of salmonella and other specified food-borne zoonotic agents were passed. This regulation covers the adoption of targets for the reduction of the prevalence of specified zoonosis in animal populations at the level of primary production, including breeding flocks (Chickens and turkeys), layers, broiler and turkey flocks. Food business operators must have samples taken and testing for the zoonosis and zoonotic agents especially Salmonella (Table 1) as summarized by Hafez (2010) [6].

 

 

Campylobacters

Thermophilic campylobacters are the most common bacterial cause of diarrhoea in humans worldwide. Enteric diseases caused by the thermophilic species C. jejuni, C. coli, C. lari, and C. upsaliensis range from asymptomatic infections to severe inflammatory bloody diarrhoea. The natural habitat of thermophilic Campylobacter is the intestinal tract of healthy birds and raw meat that can be contaminated during the slaughtering process [7]. It is estimated that as many as 90% of broilers and turkeys may harbour Campylobacter while showing little or no clinical signs of illness [8]. Poultry and poultry products remain the most common source of foodborne human campylobacteriosis. The major route for Campylobacter infection in poultry appears to be the horizontal transmission from the environment. Specific flocks that become infected show rapid rate of intra-house transmission and a high isolation rate from caecal swabs, water and litter. Campylobacter spp. are widespread in poultry not only during the growing period, but also on the poultry meat during slaughter and during processing of poultry products. Horizontal transmission is the most important mode of the introduction of Campylobacter into poultry flocks. However, the ability of Campylobacter to spread is limited by their relatively low tenacity, which can vary between strains. Especially dry environments kill Campylobacter within one or two hours [9].

 

Antibiotic resistant

The development of antibiotic resistance in bacteria, which are common in both animals and humans, is an emerging public health hazard. Controlling these foodborne organisms requires a broader understanding of how microbial pathogens enter and move through the food chain, as well as the conditions that promote or inhibit growth for each type of organism.

Multi-resistant bacteria are increasingly posing a hazard to human and animal health worldwide, impeding successful antibacterial treatment [10, 11]. In addition, the development of novel antibiotics does not keep step with the emergence of antimicrobial resistance in bacteria [12].

Among multi-resistant bacteria, vancomycin-resistant enterococci (VRE) have been estimated as one of the most common bacteria causing a rise in cases of nosocomial infections in humans in the last few years [10]. The prevalence of vancomycin-resistant enterococci (VRE) in 20 turkey flocks reared in the southwest of Germany was investigated. Enterococci were tested on the presence of the vancomycin resistance genes vanA, vanB (B1/B2/B3), and vanC (C1/C2/C3). Vancomycin-resistant enterococci were detected in 15 (75%) of the 20 turkey flocks investigated. In a total 68 isolates were isolated from birds and dust samples, enterococci bearing van-genes were detected. Of these, 12 isolates carried the vanA gene (17.6%) and 56 isolates carried the vanC1 gene (82.6%). Neither vanB (B1, B2, B3) genes nor the vanC2 or vanC3 genes could be detected [13].

In addition, Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) have been isolated from a number of livestock species and persons involved in animal production. Turkey meat was also showed to be contaminated with MRSA [14]. Richter et al. investigated the prevalence of LA-MRSA in fattening turkeys and people living on farms that house fattening turkeys [15]. Eighteen (90%) of 20 investigated flocks were positive for MRSA. All-female flocks were positive, while 8 male flocks were positive. On 12 of the farms 22 (37.3%) of 59 persons sampled were positive for MRSA. None of them showed clinical symptoms indicative of an MRSA infection. People with frequent access to the stables were more likely to be positive for MRSA. In most flock’s MRSA clonal complex (CC) 398 were detected. In five flock’s MRSA of spa-type t002 were identified, which was not related to CC398. Moreover, other methicillin-resistant Staphylococcus spp. were detected on 11 farms and in 8 people working on the farms. Similar results were about MRSA in turkeys were published by El-Adway et al. [16].

Maasjost et al. investigated the antimicrobial susceptibility patterns of Enterococcus faecalis and Enterococcus faecium isolated from poultry flocks in Germany and they found that high resistance rates were identified in both Enterococcus species for lincomycin (72%–99%) and tetracycline (67%–82%) [17]. Half or more than half of Enterococcus isolates were resistant to gentamicin (54%–72%) and the macrolide antibiotics erythromycin (44%–61%) and tylosin-tartate (44%–56%). Enterococcus faecalis isolated from fattening turkeys showed the highest prevalence of antimicrobial resistance compared to other poultry production systems.

El- Adway et al. investigated 76 C. jejuni isolates were recovered from 67 epidemiologically unrelated meat turkey flocks in different regions of Germany in 2010 and 2011 [18]. Only one isolate was sensitive to all tested antibiotics. The numbers of isolates that were sensitive to streptomycin, erythromycin, neomycin, and amoxicillin were 69 (90.8%), 61 (80.2%), 58 (76.4%), and 44 (57.9%), respectively. The emergence of a high resistance rate and multidrug resistance to three or more classes of antimicrobial agents were observed. The resistance against sulphamethoxazole/trimethoprim, metronidazole, ciprofloxacin, naladixic acid, and tetracycline was 58 (76.3%), 58 (76.3%), 53 (69.7%), 51 (67.1%), and 42 (55.3%), respectively. Multidrug resistance to three or more classes of antimicrobial agents was found and ranged from 3.9% to 40.8%. Similar results were also found by examination of isolates collected from different free-range turkey flocks in Germany [19].

General approaches to control foodborne infections

To control the foodborne organisms, information is required to understand more fully, how microbial pathogens enter and move through the food chain, and the conditions, which promote or inhibit growth for each type of organism. In general, the main strategy to control foodborne infections in poultry should include monitoring, cleaning the production chain from the top, especially for vertically transmitted microorganism such as Salmonella by culling infected breeder flocks, hatching egg sanitation and limiting introduction and spread of infections at the farm level through effective hygiene measures [20-22]. An intensive and sustained rodent control is essential and needs to be well planned and routinely performed and its effectiveness should be monitored. In addition, reducing bacterial colonization by using feed additives such as short chain organic acids (formic acid, propionic acid), carbohydrates (lactose, mannose, galactose, saccharose), probiotics, competitive exclusion or use of vaccines are further possibilities [23, 24]. Live and inactivated vaccines are used to control Salmonella in poultry [25]. Generally, vaccination alone is of little value, unless it is accompanied by improvements in all aspects of management and biosecurity. In addition, further attention must be paid to the development of efficient vaccines against campylobacter infections.

Suggested link

Since the success of any disease control programme depends on the farm and personal sanitation, it is essential to incorporate education programmes about micro-organisms, modes of transmission as well as awareness of the reasons behind such control programmes by people involved in poultry production. In addition, effective education programmes must be implemented to increase public awareness of the necessary measures to be taken for protection against bacteria in food products from poultry.

Furthermore, in spite of significant improvement in technology and hygienic practices at all stages of food production accompanied with advanced improvement in public sanitation foodborne infections remains a persistent threat to human and animal health. The failure of the human population to apply hygienically acceptable food handling and cooking practice, and the fact that the processing plants are not able to reduce the level of pathogenic bacteria in poultry products, mean that every effort must be made to reduce the Salmonella contamination of the live birds before despatch to processing plants. New approaches to the problem of contamination must be adopted and the discussion on the decontamination of the end product must be re-evaluated carefully and without emotion. In addition, research must continue to find additional control and preventive means. Furthermore, the long term, development of poultry lines that are genetically resistant to some pathogens should be progressed.

 

Conclusions

Toward food safety in the EU several legislations are into force and their aims can be summarized according to Mulder (2011) as follows [26]:

1. Safety (consumer health): by new methods to reduce the use of antibiotics/medicines; improve disease resistance; zoonosis control; traceability of animals and products
2. Safety (product safety): stimulate and control hygienic processing, traceability of products and materials intended to come into contact with food
3. Animal welfare: animals kept according to rules/systems
4. Product quality: improved quality and composition; quality and chain control systems; traceability of animals and products.
5. Environment: reducing environmental contamination, Nitrogen and Phosphorous. There is a critical look at the use of by-products of human food production. The re-use of by-products for non-food applications (feathers) should be encouraged.
6. Rural impact, economic effects and biodiversity.